Add Spotify integration with album streaming links

- Implement Spotify Web API integration for album streaming links
- Add extract_spotify_urls.py script for automated Spotify URL extraction
- Create spotify_urls_mapping.json with sample album mappings (20 albums)
- Update album cards to include both Wikipedia and Spotify links
- Add Spotify-branded styling with official green color and logo
- Implement smart fallback to Spotify search for unmapped albums
- Add responsive design for mobile with stacked link layout
- Update README with comprehensive feature documentation

Features:
• Each album now has "Listen on Spotify" link with Spotify icon
• Spotify links use official Spotify green branding
• Theme-aware styling adapts to dark/light themes
• Mobile-optimized layout with vertical link stacking
• Production-ready script for extracting all 500 album URLs

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

spotify_urls_mapping.json

@@ -0,0 +1,22 @@
+{
+  "What's Going On": "https://open.spotify.com/album/2v6ANhWhZBUKkg6pJJBs3B",
+  "Pet Sounds": "https://open.spotify.com/album/6GphKx2QAPRoVGWE9D7ou8",
+  "Blue": "https://open.spotify.com/album/1vz94WpXDVDEF245b3JakL",
+  "Songs in the Key of Life": "https://open.spotify.com/album/6YUCc2RiXcEKS9ibuZxjt0",
+  "Abbey Road": "https://open.spotify.com/album/0ETFjACtuP2ADo6LFhL6HN",
+  "Nevermind": "https://open.spotify.com/album/2UJcKiJxNryhL050F5Z1Fk",
+  "Rumours": "https://open.spotify.com/album/07w9BmFsXyDmnc0dEskJwq",
+  "Purple Rain": "https://open.spotify.com/album/7nXJ5k4XgRj5OLg9m8V3zc",
+  "Blood on the Tracks": "https://open.spotify.com/album/4WD4pslu83FF6oMa1e19mF",
+  "The Miseducation of Lauryn Hill": "https://open.spotify.com/album/1BZoqf8Zje5nGdwZhOjAtD",
+  "Revolver": "https://open.spotify.com/album/3PRoXYsngSwjEQWR5PsHWR",
+  "Thriller": "https://open.spotify.com/album/2ANVost0y2y52ema1E9xAZ",
+  "I Never Loved a Man the Way I Love You": "https://open.spotify.com/album/7nq5c4WBLbfkJC7ynPWGGN",
+  "Exile on Main St.": "https://open.spotify.com/album/1mNdRhXeEsWyOjJw2UNK6V",
+  "It Takes a Nation of Millions to Hold Us Back": "https://open.spotify.com/album/1ji14JjsqKMjU5zNZ2kMgY",
+  "London Calling": "https://open.spotify.com/album/6FCzvFN3gsQ3dOF6VIlHKW",
+  "My Beautiful Dark Twisted Fantasy": "https://open.spotify.com/album/20r762YmB5HeofjMCiPMLv",
+  "Highway 61 Revisited": "https://open.spotify.com/album/6YabPKtZAjxwyWbuO9p0gO",
+  "To Pimp a Butterfly": "https://open.spotify.com/album/7ycBtnsMtyVbbwTfJwRjSP",
+  "Kid A": "https://open.spotify.com/album/6GjwtEZcIDsjCjLHvyyULs"
+}